Liquid fuel tanks typically have a fill tube attached thereto that extends to a fill port at the open end of the fill tube. Fuel is placed in the tank through a nozzle that is inserted into the open end of the fill tube at the fill port. Because most motor vehicle fuel tanks do not have a separate vent line, gas and vapor displaced by incoming fuel is forced upstream through the fill tube past the incoming liquid fuel and thence through the open end of the fill tube to the atmosphere. As a consequence, the displaced gas becomes entrained with fuel vapor, resulting in liquid and noxious fumes being forced into the atmosphere.
A drawback to this arrangement is that a person handling the fuel delivery nozzle and standing in close relationship to the fuel tank fill tube is exposed to the fuel-entrained gas displaced from the open end of the fill tube. More particularly, the person is forced to breath the noxious fumes during the refueling process. In addition, fuel inadvertently ejected from the fill tube during refueling can splash on the person's hands and clothes. This leaves an unpleasant odor and stains that are difficult to remove. Not only is this unpleasant, but it is hazardous to nearby people and objects, and it is damaging to the environment.
While there are devices that are designed to prevent the splashing of fuel, these devices do not filter the displaced filter. For instance, one device consists of a flexible skirt permanently affixed to the nozzle on the end of a fuel pump hose. This skirt does not sealably engage the fill tube when the nozzle is placed into the fill tube. Rather, this skirt is positioned adjacent the fill tube such that liquid splashing out of the fill tube is redirected into and around the fill tube. It does not prevent the escape of liquid and fuel vapor from the fill tube itself and contamination of the environment. This skirt is not used on a majority of fuel pump nozzles and cannot be easily detached and moved to another nozzle. Consequently, there is a need for a portable fuel vapor filter that efficiently and easily seals the nozzle when the nozzle is placed in the fill tube, prevents the escape of liquid fuel, and filters fuel-entrained vapor prior to venting of the vapor to the atmosphere.